Data transfer system, data transfer apparatus, data recording apparatus, and data transfer method

ABSTRACT

It is an object to provide an efficient transfer of content data. In a case of transferring the content data from a data transfer device on a primary recording medium side to a data recording device to record the content data in a secondary recording medium, a data compression system and a bit rate that are conformable to the data recording device are compared with a data compression system and a bit rate of the content data to be sent, so that a required transfer processing is brought into realization according to a result of the comparison. For instance, when both the data compression systems are equal, and the bit rate of the content data is not more than the bit rate that is conformable to the data recording device, the content data is sent as it is in an encrypted compressed data state.

TECHNICAL FIELD

This invention relates to a data transfer system, a data transferdevice, a data recording device and a data transfer method, which aresuitable for transfer/recording of content data such as music.

TECHNICAL FIELD

There is a type of usage that a HDD (Hard Disk Drive) of a personalcomputer, for instance, is treated as a primary recording medium tostore content data such as music, while the stored content data istransferred to be recorded in a different recording medium (a secondaryrecording medium) for enjoying reproducing the music and the like on thesecondary recording medium side.

In this case, content data such as music reproduced from package mediasuch as a CD-DA (Compact Disc Digital Audio) and a DVD (DigitalVersatile Disc) or content data downloaded from an external music serverand the like over a communication network, to which the personalcomputer is connected, is stored in the HDD. Then, a user connects arecording device of the secondary recording medium to the personalcomputer to copy (duplicate) or move (transfer) the content data storedin the HDD and reproduces the content data such as music with areproducing device that is compatible with the secondary recordingmedium.

As the secondary recording medium, a memory card realized by using asemiconductor memory such as a flash memory, a minidisk serving as amagneto optical disk, a CD-R (CD Recordable), a CD-RW (CD Rewritable), aDVD-RAM, a DVD-R, a DVD-RW and the like, for instance, are supposed tobe available.

A recorder/player that is compatible with these media (recording media)widely prevails as a recording device and a reproducing device that arecompatible with the secondary recording medium, and is available invarious types such as a stationary recording/reproducing device and aportable recording/reproducing device, so that each user puts recordingand/or reproduction of the content data into practice according to one'spreference and one's own equipment.

Incidentally, in a case of giving a thought to the form of usage of thecontent data as described above, for instance, copyright protection onthe content data must be taken into consideration. If the user makes useof delivering services of the content data or purchases the packagemedia, for instance, to permit the content data to be copied onto thesecondary recording medium without any restriction after storage of thecontent data in the HDD, a situation that a proper protection on rightof a copyright holder is not secured occurs. For that reason, there areproposed various techniques as well as arrangements on a data processingsuch as to make copyright protection maintainable so far as handling ofthe content data as digital data is concerned, and a standard calledSDMI (Secure Digital Music Initiative) is included as one of theproposals.

While a data path established by the SDMI will be described later, it isarranged that after consideration of copyright protection and generaluser's benefit (a right of copying for private use), transfer/recordingto the secondary recording medium should be properly performed oncontents stored in the personal computer having the HDD as the primaryrecording medium, for instance, such as content data (which will behereinafter referred to as network contents) delivered from an externalserver over a network, for instance, and content data (which will behereinafter referred to as disk contents) read out from the packagemedia, such as the CD-DA and the DVD, to be reproduced in a disk drivedevice, such as a CD-ROM drive, integrated in the personal computer or adisk drive device connected to the personal computer, for instance.

Incidentally, in a case of transferring the content data to copy fromthe primary recording medium such as the HDD to the secondary recordingmedium such as the minidisk, there arise problems as follows.

It is assumed that ATRAC 3 (or other compression system) compressedcontent data stays encrypted in the HDD serving as the primary recordingmedium.

Normally, in a case of the network contents equivalent to SDMI-compliantcontents, data thereof is originally ATRAC 3 or other compression systemencoded data, for instance, which is delivered after being encryptedwith a content key CK by a key encryption such as a DES, for instance.Thus, the above-mentioned content data is assumed to be stored in theHDD.

In addition, on the assumption that the minidisk is arranged as thesecondary recording medium, a case is considered where a personalcomputer having the HDD is connected to a minidisk recording devicethrough a USB and the like to transfer the content data stored in theHDD to the minidisk recording device for copying and recording thecontent data in the minidisk.

The minidisk has been originally developed as a medium for recordingATRAC 3 compressed data, and, in recent devices, is conformable also tothe ATRAC 3 system that has been realized by a development of the ATRACsystem.

Generally, various bit rate data formats as shown in FIG. 18 areavailable for the ATRAC 3 system, and there may be also a case where theATRAC 3 compressed content data to be stored in the HDD uses any format(any bit rate) shown in FIG. 18, for instance.

However, all that is conformable (reproducible) to the minidiskrecording/reproducing device is two formats enclosed by broken linesamong the formats shown in FIG. 18, that is, only with a bit rate of 132or 66 kbps.

In addition, the content data to be delivered and stored in the HDD maybe also supposed to be compressed data other than the ATRAC 3 compresseddata, as a matter of course.

Under these circumstances, a processing as shown in FIGS. 17A and 17B,for instance, is required in a case of transferring the content data tocopy and record them from the HDD as the primary recording medium to theminidisk as the secondary recording medium.

It is assumed that the content data stored in the HDD is ATRAC 3compressed data, and besides, a bit rate thereof is a bit rate that isunconformable to the minidisk recording device. That is, the bit rate issupposed to be any of 176, 146, 105, 94, 47 and 33 kbps.

Incidentally, the ATRAC 3 compressed data is expressed as “A3D” for theconvenience of a description. In addition, ATRAC 3 compressed data witha bit rate that is unconformable to the minidisk recording device isexpressed as “A3Dx”, while ATRAC 3 compressed data with a bit rate thatis conformable to the minidisk recording device is expressed as “A3Dy”.

Also, data “y” encrypted with a key “x” is expressed as “E (x, y)” forthe convenience of a description in the present specification.

In addition, data resulting from decrypting the encrypted data “E (x,y)” with the key “x” is expressed as “D {x, E (x, y)}”.

Thus, if the ATRAC 3 compressed data is assumed to be “A3D” as describedabove, for instance, the contents equivalent to “A3D” encrypted with thekey CK will be expressed as “E (CK, A3D)”.

In addition, data resulting from decrypting “E (CK, A3D)” with the keyCK will be expressed as “D {CK, E (CK, A3D)}”.

FIG. 17A shows a processing in a case of converting a compression systeminto a compression system that is conformable to the minidisk recordingdevice in advance of transmission of the contents on the side of thepersonal computer having the HDD (the primary recording medium).

In FIG. 17A, when the contents stored in the HDD (the primary recordingmedium) are supposed to be “E (CK, A3Dx)” resulting from encrypting“A3Dx”, which is the ATRAC 3 compressed data with the bit rate that isunconformable to the minidisk recording device, with the key CK, adecryption of “E (CK, A3Dx)” is firstly performed. That is, suppose “D{CK, E (CK, A3Dx)}=A3Dx”.

Then, the decrypted data as “A3Dx” is decoded (decompressed) fordecompression into non-compressed data, that is, linear PCM data, forinstance.

Subsequently, ATRAC 3 compression with the bit rate that is conformableto the minidisk recording device is performed on the PCM data, which isthen converted into the compressed data “A3Dy”.

Then, the above compressed data is encrypted again with the key CK intoencrypted data “E (CK, A3Dy)”.

The contents are thus sent in this state to the transmission line suchas the USB for supplying to the minidisk recording device.

FIG. 17B shows a processing in a case of converting the compressedcontent data into non-compressed data in advance of transmission on theside of the personal computer having the HDD (the primary recordingmedium).

In FIG. 17B, when the contents stored in the HDD are supposed to be “E(CK, A3D)” resulting from encrypting “A3D”, which is the ATRAC 3compressed data, with the key CK, or “E (CK, aDT)” resulting fromencrypting “aDT”, which is the compressed data other than the ATRAC 3compressed data, with the key CK, a decryption of the content data isfirstly-performed. That is, suppose “D {(CK, E (CK, A3D)}”=A3D, or “D{CK, E (CK, aDT)}”=aDT.

Then, the decrypted data as “A3D” or “aDT” is decoded (decompressed) fordecompression into non-compressed data, that is, linear PCM data, forinstance.

Subsequently, the PCM data is encrypted again with the key CK intoencrypted data “E (CK, PCM)”.

The contents are thus sent in this state to the transmission line suchas the USB for supplying to the minidisk recording device.

As long as the processing as shown in FIG. 17A, for instance, isperformed in advance of sending the content data, the data itself may besupplied as data in a format that is conformable to the minidiskrecording device, even if there is a difference in bit rate andcompression system between the content data stored in the HDD and thedata reproducible with the minidisk. In addition, in a case of decidingon adopting the processing shown in FIG. 17B, a compression processingwill be entrusted to the minidisk recording device, so that the contentdata is recorded in the minidisk after being converted into thecompressed data that is conformable to the minidisk recording device, asa matter of course.

However, in a case of making transmission in the PCM data format asshown in FIG. 17B, the PCM data is the non-compressed data, and hence,is subject to restriction of a transfer rate depending on a bandwidth ofthe transmission line and an input bandwidth of the secondary recordingmedium. In particular, the minidisk recording device needs to input thecontent data in synchronization with a sampling frequency, so that areal time (a time equal to that taken for reproduction of music and thelike) is required for a transfer from the primary recording medium tothe secondary recording medium.

In this connection, in order to reduce a time taken for the transfer,transmission in the compressed data format over the transmission line asshown in FIG. 17A is conceived to be possible, while a process toconvert the compression system and the bit rate of the content data intothose of the minidisk recording device side as described above isrequired to realize the above transmission. For that reason, theequipment (the personal computer) on the primary recording medium sideneeds to support various kinds of compression systems because of a needfor the process as shown in FIG. 17A depending on various kinds ofequipment supposed to be connected, so that a burden on a device isheavy. Also, since it is necessary to recompress data as the PCM dataonce in the process, a processing time cannot be ignored. Further, thePCM data is subject to restriction of the transfer rate depending on arecording rate of the secondary recording medium side equipment (theminidisk recording device and the like).

In addition, when a reference is made to a case where the minidiskrecording device is used as the secondary recording medium sideequipment, the pertinent data fails to be recorded in the minidisk as itis, even if a conversion of the bit rate as shown in FIG. 17A has beenput into practice. This is because the ATRAC 3 compressed data to behandled in the minidisk recording device takes a data format that isarranged in consideration of the ATRAC compressed data.

Further, the processing such as decompression and recompression alsobrings about a problem that a deterioration of a sound quality occurs.

DISCLOSURE OF THE INVENTION

In view of the above circumstances, it is an object to provide atransfer of content data from a primary recording medium to a secondaryrecording medium efficiently at high rate according to the presentinvention.

For that reason, according to the present invention, there are provideda data transfer device, a data recording device and a data transfersystem comprising the data transfer device and the data recordingdevice, as well as a data transfer method for use in the data transfersystem.

The data transfer device according to the present invention comprisesprimary recording medium drive means for performing recording and/orreproduction of data to a primary recording medium, storage controlmeans for controlling the content data so as to be stored in anencrypted compressed data state in the primary recording medium,transmission means for sending data to a data recording device that isconnected to be capable of sending data, and transmission control meansfor, in a case of sending the content data stored in the primaryrecording medium to the data recording device through the transmissionmeans, comparing a data compression system and a bit rate that areconformable to the data recording device with a data compression systemand a bit rate of the content data to be sent, and then allowing thecontent data to be sent as it is in the encrypted compressed data statein a case of a first comparison result, while allowing the content datato be sent as a state of encrypted non-compressed data in a case of asecond comparison result.

The first comparison result as used herein is considered to be acomparison result that the data compression system of the content datato be sent is equal to the data compression system that is conformableto the data recording device, and that the bit rate of the content datato be sent is not more than the bit rate that is conformable to the datarecording device.

In addition, the second comparison result is considered to be acomparison result that the data compression system of the content datato be sent is different from the data compression system that isconformable to the data recording device, or that the bit rate of thecontent data to be sent is higher than the bit rate that is conformableto the data recording device.

The data recording device according to the present invention comprisesreception means for receiving data sent from the connected data transferdevice, secondary recording medium drive means for recording data in asecondary recording medium, decrypting means for converting encryptedcontent data having been transferred from the data transfer device intoa non-encrypted state, and recording control means for allowing thesecondary recording medium drive means to record compressed data alreadyconverted into the non-encrypted state by the decrypting means in thesecondary recording medium after performing a required data additionprocessing on the compressed data in a case of the content data havingbeen received in the encrypted compressed data state from the datatransfer device, while allowing the secondary recording medium drivemeans to record non-compressed data already converted into thenon-encrypted state by the decrypting means in the secondary recordingmedium after performing a compression processing on the non-compresseddata in a case of the content data having been received in an encryptednon-compressed data state from the data transfer device.

In addition, the recording control means controls a transfer stateaccording to a reception processing state in the reception means and asignal processing state of the secondary recording medium drive means,in a case of transferring stream data as the compressed data or thenon-compressed data already converted into the non-encrypted state bythe decrypting means toward the secondary recording medium drive meansfor a processing of recording the stream data in the secondary recordingmedium.

Also, according to the present invention, the data transfer system isbuilt with the above-mentioned data transfer device and theabove-mentioned data recording device.

As a data transfer method in a case of transferring content data from adata transfer device with the content data stored in an encryptedcompressed data state in a primary recording medium to a data recordingdevice to record the content data in a secondary recording medium, thedata transfer method according to the present invention comprises thesteps of comparing a data compression system and a bit rate that areconformable to the data recording device with a data compression systemand a bit rate of the content data to be sent from the data transferdevice, sending the content data as it is in an encrypted compresseddata state, and then recording the compressed data in the secondaryrecording medium after performing a required data addition processing onthe compressed data upon completion of a conversion into a non-encryptedstate in the data recording device, when the data compression system ofthe content data to be sent is equal to the data compression system thatis conformable to the data recording device and the bit rate of thecontent data to be sent is not more than the bit rate that isconformable to the data recording device, while sending the content dataas a state of encrypted non-compressed data, and then recordingnon-compressed data in the secondary recording medium after performing acompression processing on the non-compressed data upon completion of aconversion into the non-encrypted state in the data recording device,when the data compression system of the content data to be sent isdifferent from the data compression system that is conformable to thedata recording device and the bit rate of the content data to be sent ishigher than the bit rate that is conformable to the data recordingdevice.

According to the present invention having the above configuration, anoptimum data transfer is realized depending on a relation between thecompression system and the bit rate of the stored content data on theprimary recording medium side and the compression system and the bitrate on the secondary recording medium side. In addition, the requireddata addition processing performed on the data recording device sidemakes the data conformable to a data format that is treated on thesecondary recording medium side.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a system configuration according to anembodiment of the present invention;

FIG. 2 illustrates a data path of SDMI contents according to theembodiment;

FIG. 3 is a block diagram showing primary recording medium sideequipment according to the embodiment;

FIG. 4 is a block diagram showing secondary recording medium sideequipment according to the embodiment;

FIG. 5 is a flow chart showing a processing of primary recording mediumside equipment in a case of transfer of contents according to theembodiment;

FIG. 6 is a flow chart showing a processing of secondary recordingmedium side equipment in a case of transfer of contents according to theembodiment;

FIGS. 7A and 7B illustrate a process of a signal processing in a case oftransfer of contents according to the embodiment;

FIG. 8 illustrates a dummy bit addition processing according to theembodiment;

FIG. 9 illustrates a dummy bit addition processing according to theembodiment;

FIG. 10 illustrates a dummy bit addition processing according to theembodiment;

FIG. 11 illustrates a dummy bit addition processing according to theembodiment;

FIG. 12 illustrates a compressed data transfer operation of thesecondary recording medium side equipment according to the embodiment;

FIG. 13 illustrates a compressed data transfer operation of thesecondary recording medium side equipment according to the embodiment;

FIG. 14 illustrates a compressed data transfer operation of thesecondary recording medium side equipment according to the embodiment;

FIGS. 15A and 15B illustrate a non-compressed data transfer operation ofthe secondary recording medium side equipment according to theembodiment;

FIGS. 16A and 16B illustrate a non-compressed data transfer operation ofthe secondary recording medium side equipment according to theembodiment;

FIGS. 17A and 17B illustrate a signal processing in a case of a transferof contents; and

FIG. 18 illustrates bit rates of an ATRAC 3 system.

BEST MODE FOR EMBODYING THE INVENTION

An embodiment of the present invention will be hereinafter described inthe following order.

-   1. System configuration-   2. Data path of SDMI contents-   3. Embodiment of configuration of data transfer device (Primary    recording medium side equipment/PC)-   4. Embodiment of configuration of data recording device (Secondary    recording medium side equipment/Recording/reproducing device)-   5. Processing in a case of transfer of contents-   6. Flow control of data recording device    1. System Configuration

FIG. 1 shows a system configuration. Primary recording medium sideequipment 1 is equivalent to a data transfer device of the presentinvention, and secondary recording medium side equipment 20A isequivalent to a data recording device of the present invention. Thus, aconfiguration including the primary recording medium side equipment 1and the secondary recording medium side equipment 20A in the systemconfiguration shown in FIG. 1 is equivalent to a data transfer system ofthe present invention.

The primary recording medium side equipment 1 comprises a personalcomputer, for instance.

The primary recording medium side equipment 1 will be hereinafter alsoreferred to as the personal computer 1 in some cases, for theconvenience of a description. However, it is to be understood that theprimary recording medium side equipment 1 is not always made up of thepersonal computer.

The primary recording medium side equipment 1 conducts an operationrequired as an operation of the data transfer device as mentioned hereinwith software that is activated on the personal computer for running astorage/a transfer and the like of SDMI content data, for instance.

Then, an HDD 5 integrated into (or externally mounted to) the personalcomputer 1 is arranged as a primary recording medium (and primaryrecording medium drive means). Incidentally, although use of the HDD 5as the primary recording medium is described in the embodiment, it is amatter of course that recording media equivalent to the primaryrecording medium are not limited to the HDD, and various kinds of mediasuch as an optical disk, a magneto optical disk, a semiconductor memoryintegrated into the equipment, a portable semiconductor memory (such asa memory card) and the like, for instance, are supposed to be available.

The primary recording medium side equipment 1 is arranged to permitcommunication with a content server 91 over a communication network 110,and thereby enables to download content data such as music. It is to beunderstood that the content server 91 is available in plural numbers asa matter of course, so that a user of the personal computer 1 may takeadvantage of various data download services optionally.

The content data downloaded from the content server 91 to the personalcomputer 1 covers SDMI-compliant content data, or otherwise, contentdata that is unconformable to the SDMI.

A transmission line that forms the network 110 may be a wired orwireless public line network or a leased line between the personalcomputer 1 and the content server 91. Specifically, as the network 110,the Internet, a satellite communication network, an optical fibernetwork and other various kinds of communication lines, for instance,may be applied.

In addition, content data such as music reproduced from package media 90(which will be hereinafter also referred to as a disk 90) such as aCD-DA and a DVD by an integrated or externally mounted disk drive devicemay be also stored in the HDD 5 of the personal computer 1.

The secondary recording medium side equipment 20A or 20B is connected tothe personal computer 1 to thereby make the content data stored in theHDD 5 transferable to the secondary recording medium side equipment 20Aor 20B. The secondary recording medium side equipment 20A or 20B isarranged as a recording device (a recording/reproducing device) that iscompatible with the secondary recording medium. Then, it is alsoarranged that the content data having been transferred from the personalcomputer 1 may be copied and recorded in the secondary recording medium.

Although an embodiment of the secondary recording medium side equipment20A or 20B is supposed to be available in various types, the secondaryrecording medium side equipment 20B as used herein is limited to anSDMI-compliant recording device. The SDMI-compliant recording devicewill be described later in terms of a data path with reference to FIG.2. An SDMI-compliant memory card realized by using a semiconductormemory such as a flash memory, for instance, is supposed to be availableas the secondary recording medium inserted into the SDMI-compliantrecording/reproducing device 20B. Thus, the secondary recording mediumside equipment 20B is arranged as the recording/reproducing device thatis compatible with the SDMI-compliant memory card, for instance. In thiscase, it is arranged that the SDMI contents should be recorded in anencrypted state in the secondary recording medium.

On the other hand, the secondary recording medium side equipment 20A isequivalent to the data recording device as mentioned herein, and is torecord SDMI contents, which need to be subject to copyright protection,in a decrypted state in the secondary recording medium, as will bedescribed later in detail. A minidisk is available as the secondaryrecording medium as used herein, for instance. Thus, the secondaryrecording medium side equipment 20A is arranged as a minidiskrecording/reproducing device. The secondary recording medium sideequipment 20A will be hereinafter also referred to as therecording/reproducing device 20A in some cases.

However, as the media used for the secondary recording medium sideequipment 20A for recording and reproducing, a memory card realized byusing a semiconductor memory such as a flash memory; a minidisk servingas an magneto optical disk; a CD-R (CD Recordable); a CD-RW (CDRewritable); a DVD-RAM; a DVD-R; a DVD-RW and the like are supposed tobe also available, in addition to the minidisk. Thus, the secondaryrecording medium side equipment 20A may be a recording device that iscompatible with these media.

The personal computer 1 and the secondary recording medium sideequipment 20A or 20B are connected on the basis of transmissionstandards such as USB (Universal Serial Bus) and IEEE1394, for instance.A connection that enables a transfer of content data and the like over awired or wireless transmission line that conforms to differenttransmission standards will be also enough, as a matter of course.

2. Data Path of SDMI Contents

FIG. 2 shows a data path established by the SDMI on an assumption thatthe system shown in FIG. 1 is in use, for instance.

Incidentally, this data path is a data path that is concerned with aprocessing of storing music contents and transferring the music contentsto external equipment (the secondary recording medium side equipment20A, 20B) in the personal computer 1 having the HDD 5 as the primaryrecording medium, for instance, and in other words, is realized withsoftware that runs the music content storage/transfer processing in thepersonal computer 1.

A procedure/processing on the data path in FIG. 2 is marked withnumerals of DP1 to DP9, and hence, corresponding parts will berepresented by these numerals in the following description.

It is first ascertained that content data (network contents) deliveredfrom the content server 91 over the network 110 is SDMI-compliantcontents to be subject to copyright protection or not (DP1).

The network contents to be delivered include contents received from theserver side as contents that conform to the SDMI (which will behereinafter referred to as SDMI-compliant contents) and contentsirrelevant to the SDMI (which will be hereinafter referred to asnon-SDMI contents).

Then, in a case of the SDMI-compliant contents, data thereof is alreadyencrypted with a content key CK by a key encryption such as a DES, forinstance. If the content data itself is assumed to be originally ATRAC 3or other compression system encoded data, the SDMI-compliant contentsare delivered in a state of “E (CK, A3D)”.

When the delivered network contents are the SDMI-compliant contents,these contents are stored as SDMI contents in the HDD 5 serving as theprimary recording medium (DP1→DP2).

In this case, the content data is written on the HDD 5 in the state ofdelivered “E (CK, A3D)”. Alternatively, the content data may possibly bewritten on the HDD 5 in a state of “E (CK′, A3D)” after being encryptedwith a different key CK′ upon completion of once a decryption, that is,after a replacement of a key with a different key.

On the other hand, when the network contents are the non-SDMI contents,a watermark check, that is, a screening processing based on a digitalwatermark is required (DP1→DP3).

In addition, the watermark check is directly performed on the contentdata (disk contents) read out from the package media such as the CD-DAand the DVD to be reproduced by an integrated drive such as a CD-ROMdrive integrated in the personal computer 1 or a disk drive deviceconnected to the personal computer 1, for instance (DP3).

That is, the watermark check needs to be performed on the non-SDMIcontent data.

When the content data fails to pass the watermark check, the failedcontent data is treated as data that is not granted a copy permission sofar as the SDMI data path is concerned (DP3→DP5). While various ways ofspecific treatments are conceived to be possible depending on softwaredesign, it is supposed that the content data is treated as data that isimpossible to be transferred to other media for copying/moving, althoughbeing granted a permission to be stored in the HDD 5, or otherwise, asdata that is not granted a permission to be stored in the HDD 5 in thecourse of a processing of the SDMI-compliant contents.

When the content data passes the watermark check, that is, the presenceof the digital watermark and a copy permission as a copy control bit aremade sure, the passed content data is decided to be legally copyablecontent data, and then, it is further ascertained that the content dataneeds to be treated as SDMI-compliant contents or not (DP4). Whether ornot the content data needs to be treated as the SDMI-compliant contentsmay be decided depending on software design, user setting and the like.

When there is no need to treat the content data as the SDMI-compliantcontents, the content data is excluded from the pertinent SDMI-compliantcontent data path as data treated as non-SDMI contents (DP6). A transferand the like to a recording device that is unconformable to the SDMI,for instance, may be also supposed to be applicable.

On the other hand, when there is a need to treat the content data as theSDMI-compliant contents, the content data is encrypted, and is thenstored as the SDMI contents in the HDD 5 (DP4→DP2). The content data isstored in the state of “E (CK, A3D)” or “E (CK′, A3D)” in the HDD 5, forinstance.

The above-mentioned data path realizes that the contents (SDMI networkcontents) obtained over the network 110 as contents to be treated asSDMI-compliant contents or the contents (SDMI disk contents) fetched outfrom the disk such as the CD-DA or different media as contents to betreated as SDMI-compliant contents are stored in the HDD 5 serving asthe primary recording medium.

The SDMI contents (the SDMI network contents or the SDMI disk contents)stored in the HDD 5 are transferred to the SDMI-compliantrecording/reproducing device 20B and are granted a permission to copyonto the SDMI-compliant secondary recording medium under predeterminedrules. In a case of the present embodiment, the above SDMI contents arealso made transferable to the recording/reproducing device 20A underpredetermined conditions, in addition to the SDMI-compliantrecording/reproducing device 20B.

A processing when the SDMI-compliant recording/reproducing device 20B isconnected to the personal computer 1 having the HDD 5 is as follows.

In a case of the SDMI disk contents, rules (Usage Rule) for a transferthat is adaptive to the SDMI disk contents are determined, and atransfer for copying to the SDMI-compliant recording/reproducing device20B is authorized under the usage rules (DP8).

Incidentally, a transfer for copying from the primary recording medium(the HDD 5) to the secondary recording medium (such as the memory card)to be recorded and/or reproduced with the SDMI-compliantrecording/reproducing device 20B is called “check-out”. On the contrary,a transfer for moving from the secondary recording medium to the primaryrecording medium is called “check-in”. Incidentally, in a case of movingfrom the secondary recording medium to the primary recording medium, themoved content data is brought into an erased state on the secondaryrecording medium.

With regard to the usage rules for the transfer that is adaptive to theSDMI disk contents, an upper limit on check-out counts is predeterminedso as to permit checkout up to three times per content data, forinstance. Thus, copying is permitted up to three SDMI-compliantsecondary recording mediums, for instance. In addition, when thecheck-in is conducted, it means that the check-out count on thepertinent content data is subtracted. Thus, if the content-data issubjected to the check-in from one of the three SDMI-compliant secondaryrecording mediums even after having been copied onto the threeSDMI-compliant recording mediums, the contents may be copied once moreonto the SDMI-compliant secondary recording medium. That is, the contentdata is allowed to always coexist in the three SDMI-compliant secondaryrecording mediums at the maximum.

In a case of the SDMI network contents, rules (Usage Rule) for atransfer that is adaptive to the SDMI network contents are alsodetermined, and a transfer for copying to the SDMI-compliantrecording/reproducing device 20B is authorized under the usage rules(DP7).

While the usage rules are to determine an upper limit on check-outcounts and the like in the same manner as the above, the upper limitcount and the like may be equal to or different from the usage rules ina case of the SDMI disk contents. For instance, there may be a casewhere check-out is limited to once. In this case, although the copypermission is given only to one of the other SDMI-compliant secondaryrecording mediums per content data, a transfer for copying is madepermissible again as long as the check-in is conducted from thepertinent secondary recording medium.

When the SDMI contents are transferred for copying onto theSDMI-compliant secondary recording medium according to these usagerules, data transmission is realized as it is in an encrypted state onthe transmission line. That is, the SDMI contents are transferred in thestate of “E (CK, A3D)” or “E (CK′, A3D)” as described above, forinstance.

Further, the SDMI-compliant recording/reproducing device 20B, upon areception of the SDMI contents sent encrypted, copies and records theSDMI contents as they are in the encrypted state in the secondaryrecording medium.

When the SDMI contents copied and recorded in the secondary recordingmedium are reproduced by the SDMI-compliant recording/reproducing device20B, the content data read out from the secondary recording medium isdecrypted and reproduced. That is, the content data recorded in thestate of “E (CK, A3D)” or “E (CK′, A3D)” in the secondary recordingmedium is decrypted with the key CK or CK′.

That is, the original content data is obtained as decrypted ATRAC 3 data(A3D) as “D {CK, E (CK, A3D)}”=A3D or “D {CK′, E (CK′, A3D)}”=A3D. Aprocessing inclusive of decompression to ATRAC 3 compression isperformed on the content data for reproduction output of music and thelike through demodulation as audio data, for instance.

As described above, the SDMI-compliant content data takes the form ofencrypted data on the data path up to a point when the check-out isconducted by the SDMI-compliant recording/reproducing device 20B andfurther until the secondary recording medium is reached, or a copymanagement is realized by the transfer usage rule check, so that acopyright protection on the content data may be properly made.

On the other hand, when the recording/reproducing device 20A isconnected to the personal computer 1, the following processing is taken.

Incidentally, the recording/reproducing device 20A is to record data ina decrypted state in the minidisk and the like serving as the secondaryrecording medium, for instance, differently from the SDMI-compliantrecording/reproducing device 20B. Owing to recording in the decryptedstate, the content data copied and recorded in the minidisk is madereproducible even by a normally available minidisk reproducing devicethat prevails in general, resulting in an improvement on user'sconvenience.

However, recording in the decrypted state brings about a disadvantage inview of copyright protection. In this connection, it is necessary tosatisfy predetermined conditions in a case of transferring the contentdata to the recording/reproducing device 20A.

The conditions that are granted a permission to transfer the SDMInetwork contents to the recording/reproducing device 20A for copying andrecording in the secondary recording medium in the decrypted state areconsidered to be the following three conditions, that is, (1)authentication to the recording/reproducing device 20A is accepted, (2)a copyright holder agrees copying and recording on the content data tobe transferred and (3) no check-in is permitted.

If these three transfer conditions (1)(2)(3) are satisfied, anunrestricted transfer for copying to the equipment other than theSDMI-compliant recording/reproducing device 20B is not permitted, andbesides, a copyright protection function is also kept secure. Inaddition, the copyright protection function may be given also oncondition that the content data should be placed in an encrypted stateon the transmission line that performs the transfer (a decryption isperformed on the side of recording/reproducing device 20A).

The above transfer conditions (1)(2)(3) are checked in a case oftransferring the SDMI network contents to the recording/reproducingdevice 20A (DP9).

That is, a predetermined authentication processing is performed on therecording/reproducing device 20A. In addition, a copyright holder'sintention to give the copy permission is ascertained on the basis offlag information contained in the content data. Further, thecheck-in/check-out rules are also imposed.

In a case of transferring the SDMI network contents to therecording/reproducing device 20A, data is sent as it is in the encryptedstate over the transmission line according to these conditions. That is,the SDMI network contents are transferred in the above-mentioned stateof “E (CK, A3D)” or “E (CK′, A3D)”, for instance.

Then, the encrypted SDMI network contents are decrypted by a decryptingunit 28 into original ATRAC 3 compressed data (A3D), for instance, afterbeing subject to a reception processing in the recording/reproducingdevice 20A having a configuration shown in FIG. 4, as will be describedlater. Then, the decrypted content data is supplied to arecording/reproducing unit 25 through an encoding processing performedby an encoding/decoding unit 24, and is recorded in the minidisk 100.

Thus, when the SDMI contents copied and recorded in the minidisk 100 arereproduced by the recording/reproducing device 20A, a decode processingrequired in a normally available minidisk system, that is, EFMdemodulation, ACIRC error correction, decompression to the ATRACcompressing system and the like will be enough for the data read outfrom the minidisk 100.

This means that the minidisk 100, in which the content data is copiedand recorded, is permitted to reproduce the content data in a normalmanner, even when the minidisk is loaded in the normally availableminidisk reproducing device. That is, the user may enjoy music and thelike by allowing the normally available minidisk reproducing device thatis not SDMI-compliant to reproduce the copied and recorded SDMI networkcontents in the minidisk 100, as described above.

Incidentally, in the data path shown in FIG. 2, when no transferpermission is given as a result of the usage rule check and the like inDP7, DP8 and DP9, it is needless to say that no transfer to therecording/reproducing device 20A or 20B occurs. 3. Embodiment ofconfiguration of data transfer device (Primary recording medium sideequipment/PC)

FIG. 3 shows a configuration of the primary recording medium sideequipment 1 that operates as the data transfer device. Incidentally,although an embodiment as mentioned herein relates to a case of theprimary recording medium side equipment 1 made up of a personalcomputer, the primary recording medium side equipment may be also formedas the equipment exclusively for data transfer by using dedicatedhardware to build a configuration having the similar functions.

In a case of the present embodiment, the primary recording medium sideequipment that provides the data transfer device is realized byinstallation of a software program, which allows the personal computer 1to perform functions required as functions of the data transfer device.Incidentally, the term “personal computer” or “computer” as used hereindenotes a so-called general-purpose computer in a broad sense.

The program may be preliminarily recorded in a ROM 3 or the hard disk(HDD) 5 serving as the recording medium integrated in the computer.

Alternatively, the program may be also temporarily or permanently stored(recorded) in a removable recording medium, such as a floppy disk; aCD-ROM (Compact Disc Read only Memory); an MO (Magneto Optical) Disk; aDVD (Digital Versatile Disc); a magnetic disk and a semiconductormemory. The removable recording medium may be provided as so-calledpackage media and is equivalent to the package media 90 shown in FIG. 1.

Incidentally, the program may be radio-transferred from a download siteto the computer over a digital satellite broadcasting earth satellite orwire-transferred over a network such as a LAN (Local Area Network) andthe Internet, in addition to the installation from the package media 90into the computer as described above, so that the computer may receivethe program transferred as described above with a communication unit 8for installation into the integrated HDD 5.

The computer 1 shown in FIG. 3 has a CPU (Central Processing Unit) 2integrated therein. An input/output interface 10 is connected to the CPU2 via a bus 12. When an input unit 7 made up of a keyboard, a mouse, amicrophone and the like is operated by the user to input a commandthrough the input/output interface 10, the CPU 2 executes a programstored in the ROM (Read Only Memory) according to the command.Alternatively, the CPU 2 also loads a program stored in the HDD 5, aprogram transferred over the satellite or the network and then receivedby the communication unit 8 for installation into the HDD 5, or aprogram read out from the package media 90 such as the optical diskloaded in the drive 9 for installation into the HDD 5, to the RAM(Random Access Memory) into execution. Thus, the CPU 2 performs aprocessing required as a processing of the data transfer device on theSDMI contents as will be described later.

Then, the CPU 2 allows a result of the processing to be outputted froman output unit 6 comprised of a LCD (Liquid Crystal Display) and aspeaker through the input/output interface 10, for instance, or to besent through the communication unit 8, or to be recorded in the HDD 5,at need.

In a case of the present embodiment, the communication unit 8 isarranged to permit communication with various kinds of servers over thenetwork 110 shown in FIG. 1. That is, the computer 1 enables to downloadthe network contents such as the music content from the external contentserver 91. A processing required as the processing on the SDMI-compliantcontents or the non-SDMI contents is performed on the network contentsto be downloaded in accordance with the above data path, and the abovenetwork contents are stored as the SDMI contents in the HDD 5 at leastas the SDMI-compliant processing, for instance. The SDMI contents storedin the HDD 5 provide contents to be transferred to the SDMI-compliantsecondary recording medium side equipment 20B or the authenticatedsecondary recording medium side equipment (the recording/reproducingdevice) 20A.

A connection unit 11 is a portion that is connected to permit datacommunication with the secondary recording medium side equipment 20A or20B. A USB interface, an IEEE 1394 interface and the like are supposedto be available, for instance. A wired interface that conforms todifferent standards and a wireless interface realized by using infraredrays and electric waves are also available, as a matter of course.

Incidentally, various kinds of processing for realizing the data path asdescribed with reference to FIG. 2 include also parallel or individuallyexecuted processings (a parallel processing or a processing depending onan object, for instance) without the need for a processing in timeseries respectively.

In addition, the program may be a program that is processed with asingle computer or is subjected to a distributed processing with aplurality of computers. Further, the program may be also a program thatis transferred to a remote computer into execution.

4. Embodiment of Configuration of Data Recording Device (secondaryrecording medium side equipment/recording/reproducing device)

FIG. 4 shows a configuration of the secondary recording medium sideequipment (the recording/reproducing device) 20A equivalent to the datarecording device of the present invention.

An embodiment shown relates to the recording/reproducing device 20Aconfigured as a minidisk recorder, for instance. Thus, the minidisk (themagneto optical disk) is applied as an embodiment of the secondaryrecording medium 100. The secondary recording medium 100 will behereinafter also referred to as the minidisk 100.

Incidentally, only a processing system of recorded and/or reproduceddata to the minidisk serving as the secondary recording medium 100 and aprocessing system adaptive to the data transfer from the primaryrecording medium side equipment 1 are shown in FIG. 4, while a drivesystem, a servo system and a reproducing output system and the like thatare compatible with the minidisk 100 are equal to those of the normallyavailable minidisk recording/reproducing device, and hence, theirdetailed description will be omitted.

An MD control unit (CPU) 21 is arranged as a system controller thatcontrols the whole system serving as the recording/reproducing device20A. Specifically, for recording and reproduction to the minidisk 100,the MD control unit performs controls on a rotational drive, a spindleservo, a focus servo, a tracking servo and a thread servo, controls onlaser beams of an optical head/a magnetic head and a magnetic fieldapplication operation and controls on a encoding/decoding processing ondata to be recorded and reproduced. In addition, controls on an exchangeof instructions on communication with the personal computer 1 forauthentication or generation of data, as well as various kinds ofcommands from the personal computer 1, and a processing on the contentdata to be transferred and the like are also performed.

Although not shown, an operating unit and a display unit are alsoprovided as a user interface, so that controls on monitoring of a user'soperation performed through the operating unit, a processing dependingon an operation and display on the display unit and the like are alsoperformed.

The recording/reproducing unit 25 is a portion that is equipped with anoptical head, a magnetic head, a disk rotational drive system, a servosystem and the like for practically performing recording and/orreproduction of data to the minidisk 100.

The encoding/decoding unit 24 encodes data to be recorded in theminidisk 100 and also decodes the data reproduced from the minidisk 100.In a case of the minidisk system, an ACIRC error correction codeencoding processing and an EFM modulation processing are performed onthe data to be recorded, as well known in public. The encoding/decodingunit 24 thus performs ACIRC encoding and EFM encoding on the data to berecorded for supplying them to the recording/reproducing unit 25.

In addition, in a case of reproduction, the encoding/decoding unit alsoperforms a decoding processing such as a binary-coded processing, an EFMdemodulation and an ACIRC error correction processing on data (a RFsignal) having been read out and supplied from the recording/reproducingunit 25.

A codec 23 is a portion that performs a compression processing by meansof ATRAC/ATRAC 3 compression encoding and also a decompressionprocessing.

The data to be recorded in the minidisk 100 is considered to be datahaving been subjected to the above encoding processing upon completionof the ATRAC/ATRAC 3 compression encoding. Thus, when data having notbeen subjected to the compression encoding yet, that is, PCM audio data,for instance, is inputted to the recording/reproducing device 20A asdata to be recorded, the ATRAC or ATRAC 3 compression encoding isperformed by the codec 23, so that the compressed data is supplied tothe encoding/decoding unit 24.

In addition, in a case of the reproduction, the data having been readout by the recording/reproducing unit 25 and then decoded by theencoding/decoding unit 24 is considered to be ATRAC or ATRAC 3compressed data. For that reason, digital audio data of 44.1 KHz andquantization with 16 bits, for instance, is demodulated as a result thatthe decompression processing to the ATRAC or ATRAC 3 compression isperformed by the codec 23. In a circuit of an output system not shown,the digital audio data is subjected to a D/A conversion, an analogsignal processing, an amplification processing and the like into aspeaker output signal, which is then reproduced as music and the like.

Alternatively, output in the state of the digital audio data to theother equipment is also applicable.

While the above configuration relates to components that are alsoequipped in the recording/reproducing device of the normally availableminidisk system, the recording/reproducing device 20A as used herein isprovided with a receiver 26, a DMA 27, a decrypting unit 28, a cachememory 29, a dummy bit addition unit 30 and a flow control unit 31 asportions that are compatible with the personal computer serving as theprimary recording medium side equipment 1, as well as portions thatperform a reception/decryption processing on the transferred contentdata.

The receiver 26 is a portion that is connected to a portion between therecording/reproducing device and the connection unit 11 of the personalcomputer 1 of FIG. 3 for establishing data communication with thepersonal computer 1. The receiver performs a signal processing thatconforms to a communication system such as the USB and the IEEE1394, forinstance.

Communication from the personal computer 1 covers various kinds ofcommands, the SDMI contents and the like as data received by thereceiver 26.

The data as the SDMI contents received by the receiver 26 comes to bestored in the cache memory 29 under control of the DMA (Direct MemoryAccess) 27. Incidentally, it does not matter if data is moved to thecache memory 29 under control of the CPU, instead of the DMA 27.

The decrypting unit 28 is a portion that needs to be adaptive to theencryption processing on the SDMI contents. That is, keys (the keys CK,CK′ and the like) for decrypting the SDMI contents transferred in theencrypted state are placed, so that the decrypting unit decrypts theSDMI contents having been received in the state encrypted with the keyCK and the like, such as the contents in the state of “E (CK, A3D)”, forinstance. That is, decrypted ATRAC 3 compressed data is made obtainableas “D {CK, E (CK, A3D)}”=A3D.

The key CK and the like may be a preliminarily stored key or a key sentfrom the personal computer 1 serving as the data transfer device to therecording/reproducing device 20A at a predetermined period of time maybe also applied as a key to be stored. In addition, when the personalcomputer 1 sends the key CK and the like, it does not matter if the keyCK itself is also encrypted with a different key CCK, and a decryptionof the key CK is performed using the key CCK on the side of therecording/reproducing device 20A in advance of a storage in the cachememory 29.

Incidentally, it is to be understood that the SDMI contents are notalways data resulting from encrypting the ATRAC 3 compressed data. Thereis also a case where “E (CK, PCM)” state contents resulting fromencrypting the linear PCM data with the key CK, for instance, istransferred and inputted. In this case, decrypted linear PCM data ismade obtainable as “D {CK, E (CK, PCM)}”=PCM through the processing inthe decrypting unit, as a matter of course.

When the decrypted SDMI content data is the ATRAC 3 compressed data, adummy bit addition processing is performed in the dummy bit additionunit 30 on the decrypted SDMI contents in advance of a transfer to theflow control unit 31.

When the decrypted SDMI content data is the PCM data, a transfer to theflow control unit 31 is performed without passing through the processingin the dummy bit addition unit 30.

The dummy bit addition unit 30 is a portion that adds dummy bits inorder to make the ATRAC 3 compressed data conformable to a data formatthat is treated in the minidisk system, and its specific embodiment willbe described later.

The flow control unit 31 is a portion that transfers the received anddecrypted SDMI contents toward the MD control unit 21 (to the codec 23,the encoding/decoding unit 24 and the recording/reproducing unit 25)serving as a recording processing system in order to record thedecrypted SDMI contents in the minidisk 100, and particularly, performsa control for bringing a transfer of the above SDMI content data intopractice efficiently.

A transfer operation by the flow control unit 31 will be described laterin detail.

According to the above configuration, when the SDMI content data havingbeen sent from the personal computer 1 is the “E (CK, A3D)” state data,the received and decrypted ATRAC3 compressed data is transferred to therecording processing system through the flow control unit 13 after beingsubjected to the processing by the dummy bit addition unit 30, and isrecorded in the minidisk 100 by the recording/reproducing unit 25through the encoding processing in the encoding/decoding unit 24.

In addition, when the SDMI content data having been sent from thepersonal computer 1 is the “E (CK, PCM)” state data, the received anddecrypted PCM data is transferred to the recording processing systemthrough the flow control unit 31 to perform the ATRAC 3 compressionprocessing on the PCM data by the codec 23, and thereafter, is recordedin the minidisk 100 by the recording/reproducing unit 25 through theencode processing in the encoding/decoding unit 24.

Incidentally, in a case of sending the content data, various kinds ofcommands are also sent from the personal computer 1 to therecording/reproducing device 20A.

In a case of performing the transfer of the content data as well as therecording of the content data in the minidisk 100, the CPU 2 of thepersonal computer 1 sends each of the following commands to the MDcontrol unit 21 of the recording/reproducing device 20A:

-   -   To give information of a compression system and a bit rate of        target content data to be sent, which is stored in the HDD 5    -   To give information of a compression system and a bit rate of        content data required for a case of sending the content data to        the transmission line    -   To specify a compression system in a case of recording the        content data in the minidisk 100 (to specify either of 132 kbps        of ATRAC/ATRAC 3 and 66 kpbs of ATRAC 3)

These commands are transmitted to the MD control unit 21 upon receptionby the receiver 26, so that the MD control unit 21 needs to perform asignal processing control and/or a recording processing control requiredin a case of an operation of capturing the received content data inresponse to these commands.

The MD control unit 21 may judge received content data to be the “E (CK,A3D)” state data or the “E (CK, PCM)” state data by these commands, forinstance, and therefore, performs a signal processing suited to a dataformat of the received content data as described above.

5. Processing in a Case of Transmitting Contents

As a processing in a case of transferring the content data from thepersonal computer 1 to the recording/reproducing device 20A, aprocessing of the CPU 2 of the personal computer 1 is shown in FIG. 5,and a control processing of an operation that the MD control unit 21 ofthe recording/reproducing device 20A allows each part to perform isshown in FIG. 6.

The processing of the CPU 2 of the personal computer 1 will be firstlydescribed.

In a case of transferring certain content data stored in the HDD 5, theCPU 2 decides whether or not a compression system of the stored contentdata is equal to a compression system required for a case of recordingin the secondary recording medium as Step F101 shown in FIG. 5.

In a case where the ATRAC 3-compliant minidisk recording device isconnected as the secondary recording medium side equipment 20A, the CPU2 may judge the compression system in the secondary recording medium tobe ATRAC or ATRAC 3. In this case, since the CPU 2 specifies thecompression system and the bit rate required for the case of recordingto the MD control unit 21 in response to the above commands, it isnecessary to ascertain the specified compression system and thecompression system of the content data. A description will now be givenon the assumption that the CPU 2 specifies the bit rate of 132 kbps inthe ATRAC 3 system to the MD control unit 21.

In this case, the CPU 2 decides in Step F101 whether or not thecompression system of the content data to be transferred is the ATRAC 3system.

In a case where the compression system of the content data is the ATRAC3 system, the bit rate of the content data is ascertained in subsequentStep F102. While the bit rate in a case of the ATRAC 3 system isavailable in various kinds as shown in FIG. 18, it is decided whetherthe bit rate of the content data to be transferred is equal to or lowerthan the bit rate on the secondary recording medium side, that is, 132kbps in this case.

That is, it is decided whether the bit rate of the content data is 176or 146 kbps or any other bit rate (in the range from 132 to 33 kbps).

In a case where the compression system of the content data to betransferred is judged to be the ATRAC 3 system, and where the bit rateis judged to be not more than the bit rate on the secondary recordingmedium side (the minidisk side), as the result of a decision in StepsF101 and F102, the processing is advanced to,Step F106 intact to send acontent data stream read out from the HDD 5 to the transmission linewithout the need for any data conversion processing in particular.

In this case, the content data comes to be supplied in the state of “E(CK, A3D)” to the recording/reproducing device 20A.

On the other hand, when the content data to be transferred is judged tobe compressed data other than ATRAC 3 compressed data, or the bit rateis higher than the bit rate on the secondary recording medium side (theminidisk side) although the compression system is judged to be the ATRAC3 system, as the result of the decision in Steps F101 and F102, theprocessing is advanced to Step F103 to firstly perform a decryption.

That is, the contents stored in the HDD 5, when being the ATRAC 3compressed data “E (CK, A3D)”, are decrypted into “D {CK, E (CK,A3D)}”=A3D.

On the other hand, the contents stored in the HDD 5, when being thecompressed data “E (CK, aDT)” other than the ATRAC 3 compressed data,are decrypted into “D {CK, E (CK, aDT)}”=aDT.

Subsequently, in Step F104, the data decrypted as A3D or aDT is decoded(decompressed) for decompression into linear PCM data equivalent tonon-compressed data.

Then, in Step F105, the PCM data is encrypted again with the key CK intoencrypted data “E (CK, PCM)”.

Then, the processing is advanced to Step F106 to send the “E (CK, PCM)”state content data stream to the transmission line for supplying to therecording/reproducing device 20A.

While the content data is sent from the personal computer 1 to thetransmission line as described above, the CPU 2, in this case, informsof the MD control unit 21 about the compression system and the bit rateof the content data to be supplied over the transmission line inresponse to the above commands.

A description will now be given of a processing of the MD control unit21 of the recording/reproducing device 20A serving as the reception sidewith reference to FIG. 6.

The MD control unit 21 decides in Step F201 whether or not thecompression system of the content data received from the primaryrecording medium side is the compression system required for the case ofrecording in the minidisk 100 serving as the secondary recording medium.

In addition, in Step F202, it is also decided whether or not the bitrate of the content data received from the primary recording medium sideis not more than the bit rate required for the case of recording in theminidisk 100.

That is, the MD control unit 21 may judge the compression system and thebit rate of the content data received over the transmission lineaccording to the above commands, and the compression system and the bitrate both required for the case of recording in the minidisk 100 arespecified by the commands, so that the MD control unit 21 may give adecision in Steps F201 and F202 on the basis of the above commands.

It is assumed that the compression system required for the case ofrecording in the minidisk 100 is the ATRAC 3 system, and the bit rate isspecified as 132 kbps as described above. Then, as judging from theprocessing in FIG. 5, the content data supplied over the transmissionline is the encrypted ATRAC 3 compressed data “E (CK, A3D)”, or theencrypted PCM data “E (CK, PCM)”.

Thus, in this case, in Step F201, if the supplied content data is thedata “E (CK, A3D)”, both the compression systems are judged to be equal.

Also, as judging from the processing in FIG. 5, all that is received inthe state of “E (CK, A3D)” is the content data having the bit rate ofnot more than 132 kbps. Thus, if the supplied content data is the data“E (CK, A3D)”, a decision in Step F202 is supposed to be givensimultaneously as a matter of fact.

When the content data supplied over the transmission line is “E (CK,A3D)”, that is, the compression system of the content data received fromthe primary recording medium side is equal to the compression systemrequired for the case of recording in the minidisk 100, and thecompression system of the content data is not more than the bit raterequired for the case of recording in the minidisk 100, the processingis advanced to Step F203 to perform a decryption. That is, thedecrypting unit 28 is allowed to perform the processing of “D {CK, E(CK, A3D)}”=A3D on the content data stream that is received by thereceiver 26 and is then captured in the cache memory 29.

Further, the dummy bit addition unit 30 is allowed to perform the dummybit addition processing on the decrypted content data (A3D) as StepF204.

The dummy bit addition processing in this case is considered to be aprocessing for making the ATRAC 3 compressed data conformable to theATRAC 3 system data format that is treated in the minidisk system.

The minidisk system is a system that has been developed by adopting theATRAC system originally, and is considered to be a system that is madeconformable also to the ATRAC 3 system after that, with a development ofthe ATRAC 3 system of higher compression rate. However, since the ATRACis different from the ATRAC 3 in compression rate and also in sound unitbasis data size, a signal processing system that has been originallydesigned in conformity with the ATRAC system is not enough to interpretthe ATRAC 3 compressed data as it is. For that reason, a special dataformat suited to the ATRAC system data is applied to the minidisk systemeven though the ATRAC 3 is adopted as the compression system.

Thus, the dummy bit addition processing provides a processing that meetsthe above circumstances.

Specifically, a unit of the ATRAC system data, that is, a sound unitthat provides a minimum unit on each of L and R stereophonic audio datais assumed to be data of 212 bytes. On the other hand, the ATRAC 3compressed data has higher compression rate, so that data per sound unitbecomes smaller than the data of 212 bytes. That is, it may be said thatthe dummy bit addition processing is equivalent to a processing ofchanging a data size per sound unit to 212 bytes by adding dummy bits tothe ATRAC 3 compressed data.

FIG. 8 shows an embodiment of the dummy bit addition processing when A3Dcontent data with the bit rate of 132 kbps is received.

In a case of the bit rate being 132 kbps, the number of bytes for twochannels (L/R) is 384 bytes, 192 bytes for each channel as shown in FIG.18.

A sound unit of 192 bytes is changed to the sound unit of 212 bytes oneach of L/R channels as shown in FIG. 8. That is, a sound unit of eachchannel is changed to the sound unit of 212 bytes by adding a 12-byteheader and an 8-byte footer as dummy bits before and behind the 192-bytesound unit of the received A3D content data.

FIG. 9 shows another embodiment of the dummy bit addition processingwhen A3D content data with the bit rate of 66 kbps is received. Inaddition, ATRAC 3 RAW data in this case is considered to be data of aso-called joint stereo system, that is, there is shown a case ofconfiguring data of two, e.g., L and R channels by (L+R) data and (L−R)data.

In a case of the bit rate being 66 kbps, the number of bytes of thesound unit for two channels is 192 bytes as shown in FIG. 18. Thus, asshown in FIG. 9, a sound unit is changed to the sound unit of 212 bytesby adding a 120-byte header and an 8-byte footer as dummy bits beforeand behind the 192-byte L/R sound unit of the received content data.

FIG. 10 shows the dummy bit addition processing when A3D content datawith the bit rate of 105 kbps is received.

In a case of the bit rate being 105 kbps, the number of bytes for twochannels (L/R) is 304 bytes, 152 bytes for each channel as shown in FIG.18.

A sound unit of 152 bytes is changed to the sound unit of 212 bytes oneach of L and R channels as shown in FIG. 10. That is, a sound unit ofeach channel is changed to the sound unit of 212 bytes by adding a12-byte header, a 40-byte padding and an 8-byte footer as dummy bitsbefore and behind the 152-byte sound unit of the received A3D contentdata.

FIG. 11 shows the dummy bit addition processing when A3D content datawith the bit rate of 94 kbps is received.

In a case of the bit rate being 94 kbps, the number of bytes for twochannels (L/R) is 272 bytes, 136 bytes for each channel as shown in FIG.18.

A sound unit of 136 bytes is changed to the sound unit of 212 bytes oneach of L and R channels as shown in FIG. 11. That is, a sound unit ofeach channel is changed to the sound unit of 212 bytes by adding a12-byte header, a 56-byte padding and an 8-byte footer as dummy bitsbefore and behind the 136-byte sound unit of the received A3D contentdata.

In Step F204 shown in FIG. 6, the MD control unit 21 allows the dummybit addition unit 30 to perform the above-mentioned processing.

The dummy bit added A3D content data is transferred from the flowcontrol unit 31 to the recording processing system as Step F205, and iseventually recorded in the minidisk 100 by the recording/reproducingunit 25 through the processing in the encoding/decoding unit 24. Anoperation of the flow control unit 31 will be described later.

In a case of the content data supplied over the transmission line being“E (CK, PCM)”, that is, the compression system of the content datastored in the primary recording medium is different from the compressionsystem required for the case of recording in the minidisk 100, or thebit rate is higher than the bit rate required for the case of recordingin the minidisk 100 although both the compression systems are equal, theprocessing is advanced to Step F206 to firstly perform a decryption.That is, the decrypting unit 28 is allowed to perform the processing of“D {CK, E (CK, PCM)}”=PCM on the content data stream that is received bythe receiver 26 and is then captured in the cache memory 29.

Then, the decrypted content data (PCM) is transferred to the flowcontrol unit 31 without passing through the processing in the dummy bitaddition unit 30, and is then transferred from the flow control unit 31to the recording processing system as Step F207. In this case, in therecording processing system, the PCM data is transferred to theencoding/decoding unit 24 after being subjected to the ATRAC 3compression processing by the codec 23, and is recorded in the minidisk100 by the recording/reproducing unit 25. An operation of the flowcontrol unit 31 in this case will be described later.

In a case of transferring the content data from the personal computer 1to the recording/reproducing device 20A as described above, a signalprocessing is performed on the content data on the basis of theprocessing shown in FIGS. 5 and 6. The signal processing is summarizedas shown in FIGS. 7A and 7B.

FIG. 7A shows the processing when a compression system of content datato be sent, which is stored in the primary recording medium, is equal tothe compression system of the data to be recorded in the minidisk 100,and the bit rate is not more than the bit rate required for the case ofrecording in the minidisk 100.

In this case, the encrypted ATRAC 3 compressed content data “E (CK,A3D)” is sent to the transmission line as it is without being converted,and is then supplied toward the secondary recording medium sideequipment (the recording/reproducing device 20A). Then, in therecording/reproducing device 20A, the encrypted ATRAC 3 compressed datais decrypted into the compressed data “A3D”, which is then convertedinto the dummy bit added compressed data “A3D(md)” to meet a conformityto the minidisk system, providing data to be recorded in the minidisk100.

The above-mentioned process has effects of simplifying the transferprocessing, improving a transfer efficiency by the simplified transferprocessing, reducing a transfer time and solving a problem on thedeterioration of a sound quality, because of an elimination of the needfor the processing such as decryption, decompression (conversion intoPCM), recompression and re-encryption in the primary recording mediumside equipment.

FIG. 7B shows a process of the processing in a case where thecompression system of the content data stored in the primary recordingmedium is different from the compression system required at the time ofrecording in the minidisk 100, or a case where the bit rate is higherthan the bit rate required at the time of recording in the minidisk 100,although both the compression systems are equal.

In this case, the encrypted compressed content data “E (CK, A3D)” or “E(CK, aDT)” is decrypted into A3D or aDT, which is further decoded(decompressed) for decompression into linear PCM data equivalent tonon-compressed data. Then, the PCM data is again encrypted with the keyCK into data “E (CK, PCM)”, which is then sent to the transmission lineand is eventually supplied to the secondary recording medium sideequipment (recording/reproducing device 20A). Then, in therecording/reproducing device 20A, the encrypted data is decrypted intonon-compressed data PCM, which is then subjected to the ATRAC 3compression processing, providing data to be recorded in the minidisk100.

In a case of the transfer of content data beyond an executable range ofthe process shown in FIG. 7A, the process shown in FIG. 7B enables torecord the content data in the minidisk 100 with therecording/reproducing device 20A.

6. Flow Control of Data Recording Device

A flow control in the recording/reproducing device 20A will now bedescribed.

When the content data received over the transmission line is recorded inthe minidisk 100 serving as the secondary recording medium, there is acase where the content data stream fails to be processed successivelyfor writing onto the minidisk 100 as data to be recorded, depending on atransmission bandwidth of the transmission line and a bandwidth of inputto the secondary recording medium.

When the transmission interface is assumed to be a USB (Ver. 1.1), forinstance, a bandwidth of 12 Mbps is ensured, while an effectivebandwidth is limited to a small value for some reasons such as acapacity of the cache memory 29 and how much data is transferred fromthe receiver 26 to the cache memory 29, if taking a transfer of data inexcess of an input buffer size of the receiver 26 into consideration. Inparticular, when received content data is non-compressed PCM data, alimitation on the bandwidth is increased, in comparison with a case ofcompressed data.

In addition, when a transfer from the cache memory 29 to the secondaryrecording medium (the minidisk 100) is conducted at low rate, successivewriting often becomes inexecutable.

In this connection, the present embodiment brings a high rate transferinto realization by adopting a flow control as follows.

Specifically, while the content data that is received by the receiver 26and is then transferred to the cache memory 29 is once stored in anotherregion of the cache memory 29 after being decrypted by the decryptingunit 28, and is then transferred from the MD control unit 21 to therecording processing system (the encoding/decoding unit 24 and the codec23) on the basis of control that is performed by the flow control unit31, a flow control according to the conditions of each part is requiredbetween the flow control unit 31 and the MD control unit 21.

A description will now be given of the flow control when “E (CK, A3D)”is supplied over the transmission line, that is, the decrypted and dummybit added ATRAC 3 compressed data is transferred from the flow controlunit 31 to the MD control unit 21.

In this case, as shown in FIG. 4, a data transfer is performed inresponse to each of signals such as a data request XARQ from the MDcontrol unit 21 to the flow control unit 31, as well as a byte sinkXABS, a transfer clock ACLK and a compressed stream data DATA from theflow control unit 31 to the MD control unit 21.

FIGS. 12, 13 and 14 show a timing chart in a case of transfer.Incidentally, FIGS. 12, 13 and 14 provide a continuous timing chart, anda numerical value (a point of time) corresponding to a bit timing (thetransfer clock ACLK) is shown at the upper most stage of each drawing.

In this case, the data transfer is performed in response to the datarequest XARQ from the MD control unit 21 to the flow control unit 31.When the data request XARQ is asserted, a reception of data from thetransmission line such as the USB is performed, and the flow controlunit 31 starts a transfer of the compressed stream data DATA to the MDcontrol unit 21 in synchronization with the transfer clock ALCK,whenever 2 bytes are reserved in the cache memory 29 for decrypted data(the compressed stream data DATA) to be transferred to the recordingprocessing system. At the same time, the flow control unit 31 outputsalso the byte sink XABS in byte units.

Assuming that 2 bytes are reserved for the compressed stream data DATAup to a point of time “n+3” when the data request XARQ resides at apoint of time “2” as shown in FIG. 12, for instance, a transfer of thecompressed stream data DATA is started from a point of time “n+4”, andthe byte sink XABS is also outputted. As shown in the drawing, data of 1byte is transferred from a MSB in synchronization with the transferclock ALCK, and the byte sink XABS is also outputted according to atiming of low-order 4-bits.

After the start of the transfer as shown in FIG. 12, successive datatransfer is performed as shown in FIG. 13, for instance.

Now it is assumed that the data transfer to the MD control unit 21 istemporarily interrupted according to circumstances of a receivingprocessing system from a point of time “n+36” as shown in FIG. 13. It isconsidered to be a case where the data transfer from the USBtransmission line is too late, or a situation that the transfer from thereceiver 26 to the cache memory 20 is too late occurs.

In this case, as shown in a point of time “n+38” in FIG. 14, the flowcontrol unit 31 terminates the transfer by stopping output of the bytesink XABS. The MD control unit 21 in this case recognizes that thetransfer is being interrupted by the fact that no byte sink XABS isacquired, in the pertinent transfer period of 1 byte.

Thereafter, if the transfer is resumed from a point of time “m+1”, thebyte sink XABS is outputted in a 1-byte period in this case, so that theMD control unit 21 captures the data in the 1-byte period in recognitionof this data as the effective compressed stream data DATA.

On the other hand, when an interruption of the transfer is requiredaccording to circumstances of the recording processing system, such as acase of needing to interrupt the transfer temporarily from the flowcontrol unit 31 for reasons of a transfer time of the processing ofrecording into the minidisk 100, for instance, the MD control unit 21terminates the transfer by interrupting the data request XARQ.

In a period of time “m+15” shown in FIG. 14, for instance, if the datarequest XARQ is set to “H”, a transfer request is turned off, andaccordingly, the flow control unit 31 stops output of the compressedstream data DATA and the byte sink XABS in response to the off state ofthe transfer request. It is a matter of course that the data requestXARQ is set to “L” again whenever an allowance will be-made for theprocessing of the recording processing system, so that the transfer ofthe compressed stream data DATA is resumed.

As described above, the transfer between the flow control unit 31 andthe MD control unit 21 may be made interrupted flexibly according to thecircumstances of the receiving processing system or the recordingprocessing system. That is, the flow control permits a regulation of thedata transfer depending on each of the bandwidth of the transmissionline and the reception processing or the processing of recording intothe minidisk 100, so that an efficient data transfer is made executable.

A description will now be given of the flow control in a case where “E(CK, PCM)” is supplied over the transmission line, that is, thedecrypted PCM data is transferred from the flow control unit 31 to theMD control unit 21.

In this case, as shown in FIG. 4, the data transfer is performed inresponse to each of signals such as an L/R clock LRCK, a data block XBCKand PCM stream data DATA from the flow control unit 31 to the MD controlunit 21.

FIGS. 15A, 15B, 16A and 16B show a timing chart in a case of transfer.Incidentally, FIGS. 15A, 15B, 16A and 16B provide a successive timingchart, and a numerical value (a point of time) corresponding to the dataclock XBCK is shown on the upper most stage of each drawing.

In this case, the decrypted PCM stream data DATA stored in the cachememory 29 is outputted from the flow control unit 31 to the MD controlunit 21 in synchronization with the data clock XBCK correspondingly tothe L/R clock LRCK.

The PCM stream data DATA is identified to be data on an L channel whenthe L/R clock LRCK is set to “H” level, and also to be data on an Rchannel when the L/R clock is set to “L” level. Each channel based onthe L/R clock LRCK is supposed to hold for a 32-data block period, while16-bit PCM data of each channel is transferred after an insertion into a16-data clock period, which is the latter half of the 32-data clockperiod.

While a transfer of 16-bit data of the L channel is performed in aperiod from a point of time “0” shown in FIG. 15A to a point of time“31” shown in FIG. 15B, the 16-bit data is sent in synchronization withthe data clock XBCK in a period from a point of time “16” to a point oftime “31”.

If an input of data to the MD control unit 21 is performed insynchronization with the L/R clock LRCK in sampling frequency units, atransfer of the content data to the MD control unit 21 occurs in realtime. Thus, assuming that the L/R clock LRCK is set to be N times asmuch as a sampling frequency, a time of 1/N times as much as the realtime will be enough to transfer the content data to the MD control unit21 at high rate.

While FIGS. 15B and 16A show a period, during which the PCM stream dataDATA is transferred successively, the flow control unit 31 terminatesthe transfer by stopping output of the data clock XBCK as shown in FIG.16B in a case where the transfer of data to the MD control unit 21 istemporarily interrupted according to the circumstances of the receivingprocessing system, that is, the transfer of data from the USBtransmission line is too late, for instance, or a situation that thetransfer from the receiver 26 to the cache memory 29 is too late occurs.The MD control unit 21 in this case recognizes that the transfer isbeing interrupted by the fact that no data clock XBCK is acquired.

Thereafter, when the transfer is made executable, the flow control unit31 resumes the output of the data clock XBCK and also resumes thetransfer of the PCM stream data DATA in synchronization with the dataclock XBCK on the basis of the L/R clock LRCK. The MD control unit 21captures the PCM stream data DATA in response to the data clock XBCK andthe L/R clock LRCK.

Whenever the PCM stream data DATA having been inputted to the MD controlunit 21 reaches a data size of an individual sound block, thecompression processing by the codec 23 is started. In a case of theATRAC, for instance, the compression processing is started whenever512-word * 16-bit data per channel is stored in an input buffer memoryarranged for the compression processing.

A permissible time taken for the compression processing is supposed tobe “sampling clock period” *“sound block size” * 1/2 * 1/N. N denotes avalue in a case where the L/R clock LRCK is set to be N times as much asthe sampling frequency as described above. In addition, 1/2 is usedbecause of a need for the compression of two channel data in atime-division manner.

Thus, an increase in speed of the L/R clock LRCK within the allowablerange of the conditions causes no termination of the transfer bycompression rate limitations.

That is, in this case, there is theoretically no need to interrupt thetransfer due to the circumstances of the recording processing system.

Then, even in a case of the transfer of the PCM stream data DATA, thetransfer thereof may be made flexibly interrupted according to thecircumstances of the transmission line and the reception processingsystem. In addition, a high rate transfer is also made possibledepending on setting of the L/R clock LRCK. Accordingly, an efficientdata transfer is made executable.

Having described the illustrations as the embodiments, it is to beunderstood that the present invention is not limited to the aboveembodiments.

For instance, target data for the transfer from the primary recordingmedium to the secondary recording medium is not limited to the SDMIcontents as described above, and various kinds of content data may bealso widely employed.

The primary recording medium is also supposed to be available in varioustypes, in addition to the HDD.

It is a matter of course that the secondary recording medium and thesecondary recording medium side equipment 20A are also supposed to beavailable in various types, without being limited to the minidisk andthe minidisk recording device. The secondary recording medium 100 may bethe CD-R; the CD-RW; the DVD-RAM; the DVD-R; the DVD-RW; various kindsof memory cards and the like. Thus, the secondary recording medium sideequipment 20A may be a recording device that is compatible with thesemedia.

Having mentioned the present invention also as related to theSDMI-compliant recording/reproducing device 20B, it is to be understoodthat the present invention may be also applied to a transfer of thecontent data to the recording/reproducing device 20B.

According to the present invention as has been understood from the abovedescription, in a case of transferring the content data from the datatransfer device on the primary recording medium side to the datarecording device to record the content data in the secondary recordingmedium, the data compression system and the bit rate that areconformable to the data recording device are compared with the datacompression system and the bit rate of the content data to be sent, sothat a required transfer processing is brought into realizationaccording to a result of the comparison. Specifically, when the datacompression system of the content data to be sent is equal to the datacompression system that is conformable to the data recording device, andthe bit rate of the content data to be sent is not more than the bitrate that is conformable to the data recording device, the content datais sent as it is in the encrypted compressed data state, and thecompressed data is recorded in the secondary recording medium after therequired data addition processing is performed on the compressed dataupon completion of the conversion into the non-encrypted state in thedata recording device. In this case, a conversion of the compressed dataformat inclusive of a conversion into the PCM data, for instance, is notrequired, and data is sent in the compressed data format over thetransmission line, so that a higher efficiency of the content datatransfer processing as well as a reduction of the time taken for thetransfer may be realized. In addition, a problem such as thedeterioration of a sound quality does not occur, because of no need ofthe processing steps such as decompression and recompression.

On the other hand, in a case where the data compression system of thecontent data to be sent is different from the data compression systemthat is conformable to the data recording device, or where the bit rateof the content data to be sent is higher than the bit rate that isconformable to the data recording device, the content data is sent asthe state of encrypted non-compressed data, and the non-compressed datais recorded in the secondary recording medium after the compressionprocessing is performed on the non-compressed data upon completion ofthe conversion into the non-encrypted state in the data recordingdevice, so that transfer and/or recording to the secondary recordingmedium may be realized also as to the content data in the compressionsystem that is unconformable to the secondary recording medium side.

In a case of transferring the stream data as the received and decryptedcompressed data or non-compressed data toward the secondary recordingmedium drive means for the processing of recording the stream data inthe secondary recording medium, the data recording device controls thetransfer state depending on the reception processing state in thereception means and the signal processing state of the secondaryrecording medium drive means, so that the optimum data transfer andrecording processing is realized in accordance with the transmissionline, signal processing capabilities and the like.

1. In a data transfer system comprising a data transfer device and adata recording device, said data transfer system characterized in that:said data transfer device includes: primary recording medium drive meansfor performing recording and/or reproduction of data to a primaryrecording medium; storage control means for controlling content data soas to be stored in said primary recording medium in an encryptedcompressed data state; transmission means for sending data to said datarecording device; and transmission control means for, in a case ofsending the content data stored in said primary recording medium to saiddata recording device through said transmission means, comparing a datacompression system and a bit rate that are conformable to said datarecording device with a data compression system and a bit rate ofcontent data to be sent, and then allowing said content data to be sentas it is in the encrypted compressed data state in a case of a firstcomparison result, while allowing said content data to be sent as astate of encrypted non-compressed data in a case of a second comparisonresult, and said data recording device includes: reception means forreceiving data sent from said data transfer device; secondary recordingmedium drive means for recording data in a secondary recording medium;decrypting means for converting the encrypted content data having beentransferred from said data transfer device into a non-encrypted state;and recording control means for allowing said secondary recording mediumdrive means to record the compressed data already converted into thenon-encrypted state by said decrypting means in said secondary recordingmedium after performing a required addition processing on saidcompressed data in a case of the content data having been sent inaccordance with said first comparison result, while allowing saidsecondary recording medium drive means to record non-compressed dataalready converted into the non-encrypted state by said decrypting meansin said secondary recording medium after performing a compressionprocessing on said non-compressed data in a case of the content datahaving been sent in accordance with said second comparison result. 2.The data transfer system according to claim 1, characterized in thatsaid first comparison result is a comparison result that the datacompression system of the content data to be sent is equal to the datacompression system that is conformable to said data recording device andthat the bit rate of the content data to be sent is not more than thebit rate that is conformable to said data recording device.
 3. The datatransfer system according to claim 1, characterized in that said secondcomparison result is a comparison result that the data compressionsystem of the content data to be sent is different from the compressionsystem that is conformable to said data recording device, or that thebit rate of the content data to be sent is higher than the bit rate thatis conformable to said data recording device.
 4. The data transfersystem according to claim 1, characterized in that said recordingcontrol means controls a transfer state in accordance with a receptionprocessing state in said reception means and a signal processing stateof said secondary recording medium drive means in a case of transferringstream data as the compressed data or non-compressed data alreadyconverted into the non-encrypted state by the decrypting means towardsaid secondary recording medium drive means for a processing ofrecording said stream data in said secondary recording medium.
 5. A datatransfer device, characterized by comprising: primary recording mediumdrive means for performing recording and/or reproduction of data to aprimary recording medium; storage control means for controlling contentdata so as to be stored in said primary recording medium in an encryptedcompressed data state; transmission means for sending data to a datarecording device that is connected to be capable of sending data; andtransmission control means for, in a case of sending the content datastored in said primary recording medium to said data recording devicethrough said transmission means, comparing a data compression system anda bit rate that are conformable to said data recording device with adata compression system and a bit rate of content data to be sent, andthen allowing said content data to be sent as it is in the encryptedcompressed data state in a case of a first comparison result, whileallowing said content data to be sent as a state of encryptednon-compressed data in a case of a second comparison result.
 6. The datatransfer device according to claim 5, characterized in that said firstcomparison result is a comparison result that the data compressionsystem of the content data to be sent is equal to the data compressionsystem that is conformable to said data recording device and that thebit rate of the content data to be sent is not more than the bit ratethat is conformable to said data recording device.
 7. The data transferdevice according to claim 5, characterized in that said secondcomparison result is a comparison result that said data compressionsystem of the content data to be sent is different from the datacompression system that is conformable to said data recording device, orthat the bit rate of the content data to be sent is higher than the bitrate that is conformable to said data recording device.
 8. As a datatransfer method in a case of transferring content data in an encryptedcompressed data state from a data transfer device with the content datastored in the encrypted compressed data state in a primary recordingmedium to a data recording device for recording said content data in asecondary recording medium, the data transfer method characterized bycomprising the steps of: comparing a data compression system and a bitrate that are conformable to said data recording device with a datacompression system and a bit rate of content data to be sent from saiddata transfer device; sending the content data as it is in the encryptedcompressed data state, and then recording the compressed data in saidsecondary recording medium after performing a required data additionprocessing on said compressed data upon completion of a conversion intothe non-encrypted state in said data recording device, when the datacompression system of said content data to be sent is equal to the datacompression system that is conformable to said data recording device,and the bit rate of said content data to be sent is not more than thebit rate that is conformable to said data recording device; and sendingthe content data as the state of encrypted non-compressed data, and thenrecording non-compressed data in said secondary recording medium afterperforming a compression processing on said non-compressed data uponcompletion of a conversion into the non-encrypted state in said datarecording device, when the data compression system of said content datato be sent is not different from the data compression system that isconformable to said data recording device, or when the bit rate of saidcontent data to be sent is higher than the bit rate that is conformableto said data recording device.